The present invention relates to a card edge connector, and more specifically to a card edge connector mounted onto a mother board having a detachably connected daughter board.
Card edge connectors, such as those commonly used in personal computers or the like, are mounted on a mother board and have a daughter board such as Single Inline Memory Module (SIMM) or Double Inline Memory Module (DIMM) detachably connected. An example of one such connector is shown in FIG. 9 (see Japanese Patent Laid-Open No. 8-190967).
This card edge connector 101, as shown in FIG. 9A, has an insulated housing 110 mounted on a mother board (not shown). The housing has two daughter board receiving recesses 111, 211 extending in the longitudinal direction. A plurality of contacts 121, 221 is attached in two upper and lower rows along the longitudinal direction of the daughter board receiving recesses 111, 211 and are connected to the mother board. At both ends of the daughter board receiving recess 111 of the housing 110 are latch portions 131 for holding a daughter board 300 that has been placed in a horizontal position by being rotated after being obliquely inserted into the daughter board receiving recess 111, at a horizontal angle. Similarly, at both ends of the daughter board receiving recess 211 are latch portions 231 for holding the daughter board 300 that has been placed at a horizontal angle by being rotated after being obliquely inserted into the daughter board receiving recess 211, at a horizontal angle.
Each latch portion 131, 231 is formed integrally with the housing 110. At the front end of the latch portion (right end in FIG. 9B), there are provided restraining portions 132, 232 and daughter board locking portions 133, 233. Each of the restraining portions 132, 232 projects inwardly from the top part of the front end of the latch portion 131, 231. When the daughter board 300 is inserted into the daughter board receiving recess 111, 211 and rotated to a horizontal position from an oblique position, each of the restraining portions 132, 232 is resiliently displaced away from the board and is then returned to its original or unstressed state by means of an elastic force of the latch portions 131, 231. In the unstressed position, the restraining portions 132, 232 come into contact with the top surface of the edge portion of the daughter board 300 to prevent the daughter board 300 from being inadvertently rotated from the horizontal position. Each of the daughter board locking portions 133, 233 projects, as shown in FIG. 9B (in FIG. 9B only the daughter board locking portion 133 is shown), inwardly from a position adjacent to the restraining portion 132, 232 of the latch portion 131, 231. When the daughter board 300 is placed in a horizontal position with respect to the mother board, each of the daughter board locking portions 133, 233 enters a semicircular recess 301 formed at the edge portion of the daughter board 300. When a force is applied to the daughter board 300 in the horizontal direction (direction indicated by an arrow in FIG. 9B), press surfaces 133A, 233A (only 133A is shown) thereof act so as to press an abutting surface 301A formed on the inner wall of the semicircular recess 301, preventing the daughter board 300 from being removed from the connector 101 in the horizontal direction.
While the prior art connector described above maintains the board in position when fully inserted into the connector 101, it is not difficult to overcome the locking portions. Therefore, it is likely that the daughter board will disengage from the connector due to an impact such as falling, which is unacceptable in many applications.
An object of the present invention is to provide a card edge connector capable of effectively restraining a daughter board from disengaging from a conductor in the horizontal direction even under adverse conditions by increasing the holding pressure applied by a latch member to the daughter board. The card edge connector of the present invention has an insulated housing mounted onto a mother board and a latch member attached to the housing for holding the daughter board. The latch member has a daughter board locking portion for restraining the daughter board from inadvertent removal in the horizontal direction. The latch member engages with an inner wall of a semicircular recess formed at an edge portion of the daughter board. The daughter board locking portion has a pointed edge portion that cooperates with the inner wall of the semicircular recess to maintain the daughter board in position.
In the embodiment, the latch member is a metal latch which is stamped and formed from a metal plate. The pointed edge portion is a burr edge provided at a tip end of the latch member that is formed when the metal plate is stamped. The pointed edge portion is inclined in a direction perpendicular to the horizontal direction, and enters in the vicinity of a top end of the inner wall of the semicircular recess.